Toxicity Test of Five Fungicides against Two Strain Rhizoctnia solani Kühn

Key words: 
• fungicides /
• Rhizoctnia solani /
• toxicity

Abstract: The mycelium growth rate method was used to measure and compare the toxicities of 5 fungicides against R-HKB and R-DZC，of Rhizoctnia solani Kühn，which were 25％ propiconazole，12.5％ tebuconazole，80％ ethylicin，25％ prochloraz and 5％ Jinggangmycin，The results showed that propiconazole was the most effective on inhibiting the radial growth of strain R-HKB mycelium，and its EC₅₀ was 0.013 2mg·L^-1；tebuconazole was the most effective on inhibiting the radial growth of R-DZC mycelium，and its EC₅₀ was 0.413 1mg·L^-1；The toxicity of Jinggangmycin was the lowest against the growth of R-HKB and R-DZC mycelium，whose EC₅₀ were 714.494 8 mg·L^-1 and 663.417 1 mg·L^-1 respectively.The toxicity of Jinggangmycin was 54 128.4 and 1 606.0 times less than that of propiconazole and tebuconazole separately.These data indicated that propiconazole and tebuconazole were more effective for the growth inhibition of R.solani in Aquilaria sinensis and Zoysiagrass sinica.